This invention generally relates to feedstock for domesticated ruminants. More specifically this invention relates to an unsaturated lipid supplemented feedstock for ruminants which beneficially provides an increased production of propionate in the rumen and a resultant improved feed efficiency and body growth in the ruminant.
Conventional cattle feeds such as corn and alfalfa often fail to provide sufficient energy for cattle, especially lactating dairy cattle during periods of heavy milk production. Feed containing a high proportion of corn also has a tendency to depress the milk fat content of the milk produced by such cattle. Lipid is an excellent energy source, and it is known that if the proportion of lipid in cattle food is increased, lactating dairy cattle produce high milk yields without draining their reserves of body fat and without diminishing the proportion of milk fat in the milk produced.
However, it has been found that if the proportion of lipid in the diet of cattle exceeds about 3-5% of the total feed solids, the feed has toxic effects upon the microorganisms in the rumen of the cattle. It appears that lipid reduces the growth rate or even kills certain microorganisms which digest fiber in the cow""s rumen, thereby lowering fiber digestibility. This deleterious effect on the cow""s rumen is particularly true of unsaturated lipids. Although the decreased fiber digestion in the rumen is partially compensated by greater fiber digestion in the lower parts of the alimentary canal, such later fiber digestion produces a blend of different fatty acids than that which is produced by the digestion in the rumen, and the different blend of fatty acids is less suited to the cow""s metabolism.
U.S. Pat. Nos. 4,642,317; 4,826,694; 4,853,233; and 4,909,138 describe the incorporation of insoluble fatty acid salts in ruminant feed as a means of increasing the fat content of the feed without deleteriously affecting the ruminant digestion cycle. A feed additive such as fatty acid calcium salt functions as a rumen-bypass product, and is subsequently metabolized in the abomasum or small intestine of the ruminant.
Many dietary lipids contain a large proportion of unsaturated fatty acids. Under the usual feeding conditions for lactating cattle, however, these unsaturated fatty acids do not appear in cow milk because they are extensively biohydrogenated to more saturated fatty acids (e.g., stearic acid) by the ruminal microbial population.
Of related interest with respect to the present invention are publications that describe studies of factors which influence biohydrogenation of unsaturated fatty acids under ruminal conditions.
J. Dairy Sci., 78, 2797 (1995) reports in vitro experiments directed to the antimicrobial inhibition of lipolysis and lipid biohydrogenation of soybean oil in rumen fluid. The most potent inhibitors are ionophores and amoxicillin.
An xe2x80x9cionophorexe2x80x9d is illustrated by monensin which is a cyclic polyether antibiotic that is naturally by occurring in Streptomyces cinnamonensis. 
Ionophores have been utilized extensively in the diets of ruminants, and effects on animal performance are well documented. Improved animal performance in part derives from the ability of ionophores to alter ruminal fermentation. Dietary ionophores increase the ratio of propionate to acetate, and inhibit ruminal methanogenesis. Changes in ruminal fermentation pathways are attributed to the disruptive action of ionophores on the permeability of ions across bacterial membranes. Different ionophores vary in their affinity and binding selectivity for cations.
There is limited information on the effect of ionophores on ruminal lipid metabolism. Dietary unsaturated fatty acids are extensively biohydrogenated by ruminal bacteria, a process that requires energy for reduction and can serve as means for disposal of hydrogen. It has been suggested that ionophores reduce methane production by inhibiting the growth of Gram-positive bacteria that produce hydrogen, and thereby decrease ruminal biohydrogenation of unsaturated fatty acids. Limited studies have indicated that dietary ionophores alter lipid metabolism in the rumen, with a resulting increase of unsaturated fatty acids in ruminal bacteria and in the duodenal digesta.
There is continuing interest in developments relating to improved materials and procedures for advancing ruminant husbandry, and for providing value-added meat and dairy products for human consumption.
Accordingly, it is an object of this invention to provide a ruminant feedstock which yields improved feed efficiency and body growth in ruminants.
It is another object of this invention to provide an unsaturated lipid supplement for ruminant feedstock with lipids that exhibit rumen-bypass properties, and which has a content of ionophorous antibiotic additive.
It is another object of this invention to provide a method for improving the lactational performance of ruminants.
It is a further object of this invention to provide a cow milk product which has a milk fat profile with an increased molar proportion of unsaturated fatty acid constituents.
Other objects and advantages of the present invention shall become apparent from the accompanying description and example.
One or more objects of the present invention are accomplished by the provision of a feedstock adapted for beneficial feeding to a ruminant, which feedstock comprises (1) nutritionally balanced ration; (2) between about 2-20 weight percent, on a dry weight basis, of lipid ingredient comprising unsaturated fatty acid derivative having rumen-bypass properties; and (3) an effective quantity of cyclic polyether ionophorous antibiotic ingredient; wherein a ruminant feeding regimen with the feedstock induces an increased production of propionate in the rumen, and a resultant improved feed efficiency and body growth in the ruminant.
A typical feedstock for ruminants such as lactating cattle will include silage, and energy concentrate and protein concentrate. A basal feedstock can comprise (6.4) corn silage (35% dry matter), (17) alfalfa silage (50% dry matter), (1) alfalfa hay, and (6.9) energy and (2.1) protein concentrate.
The compositions of an energy concentrate and a protein concentrate are illustrated in TABLE 1.
One or more other ingredients can be incorporated in a present invention feedstock composition, such as biologically active derivatives.
An optional biologically active ingredient can be included in a feedstock in an effective quantity between about 0.05-20 weight percent, based on the weight of feedstock. It can be selected from a broad variety of nutrients and medicaments, either as a single component or as a mixture of components, which are illustrated by the following listing of active species:
1. sugars and complex carbohydrates which include both water-soluble and water-insoluble monosaccharides, disaccharides and polysaccharides.
Cane molasses is a byproduct from the extraction of sucrose from sugar cane. It is commercially available at standard 79.5xc2x0 Brix concentration, which has a water content of about 21 weight percent, and a sugar content of 50 weight percent. Sugar beet byproducts also are available as low cost carbohydrate sources.
Whey is a byproduct of the dairy industry. The whey is a dilute solution of lactalbumin, lactose, fats, and the soluble inorganics from milk. Dried whey solids typically have the following composition:
Another source of carbohydrate is derived from the pulp and paper industry which produces large quantities of byproduct lignin sulfonates from wood during the sulfite pulping process. The carbohydrate byproduct is a constituent of the spent sulfite liquor.
2. aminoacid ingredients either singly or in combination which include arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, tyrosine ethyl HCl, alanine, aspartic acid, sodium glutamate, glycine, proline, serine, cysteine ethyl HCl, and the like, and analogs and salts thereof.
3. vitamin ingredients either singly or in combination which include thiamine HCl, riboflavin, pyridoxine HCl, niacin, niacinamide, inositol, choline chloride, calcium pantothenate, biotin, folic acid, ascorbic acid, vitamin B12, p-aminobenzoic acid, vitamin A acetate, vitamin K, vitamin D, vitamin E, and the like.
Trace element ingredients include compounds of cobalt, copper, manganese, iron, zinc, tin, nickel, chromium, molybdenum, iodine, silicon, vanadium and selenium.
4. protein ingredients as obtained from sources such as dried blood or meat meal, dried and sterilized animal and poultry manure, fish meal, liquid or powdered egg, fish solubles, cell cream, soybean meal, cottonseed meal, canola meal, and the like.
Protein ingredients include non-protein nitrogen compounds such as urea, biuret, ammonium phosphate, and the like.
5. antioxidants as illustrated by butylated hydroxyanisole, butylated hydroxytoluene, tocopherol, tertiary-butylhydroquinone, propyl gallate, and ethoxyquin; and suitable preservatives include sodium sorbate, potassium sorbate, sodium benzoate, propionic acid, xcex1-hydroxybutyric acid, and the like.
6. suspension stabilizing agents which preferably are selected from nonionic surfactants, hydrocolloids and cellulose ethers. These types of chemical agents are illustrated by polyethylene oxide condensates of phenols, C8-C22 alcohols and amines; ethylene oxide reaction products with fatty acid partial esters of hexitans; alkylarylpolyoxyethylene glycol phosphate esters; gum arabic; carob bean gum; tragacanth gum; ammonium, sodium, potassium and calcium alginates; glycol alginates; xanthan gum; potato agar; alkylcellulose; hydroxyalkylcellulose; carboxyalkylcellulose; and the like.
The feedstock initially is metabolized in the rumen of cattle and other ruminants. The rumen contains microorganisms, such as bacteria and protozoa, which break down complex compounds ingested by the animal via a fermentation process.
The essential lipid ingredient of an invention feedstock comprises unsaturated fatty acid derivative having rumen-bypass properties. The lipid derivative can be in the form of fatty acid alkaline earth metal salt, such as calcium and/or magnesium salt. The lipid derivative also can be in the form of fatty acid amide, in which the amide nitrogen is substituted with hydrogen and/or aliphatic radicals. Fatty acid salts and amides having rumen-bypass properties are described in publications such as U.S. Pat. Nos. 4,642,317; 4,826,694; 5,391,788; 5,425,693; 5,456,927; 5,496,572, 5,547,686; 5,670,191; 5,874,102; and the like, incorporated by reference.
A preferred group of unsaturated fatty acids are 18-carbon structures such as oleic acid, linoleic acid, conjugated linoleic acid, linolenic acid, alpha-linolenic acid, and the like. Also preferred are unsaturated fatty acids such as eicosapentaenoic acid, docosapentaenoic acid, tetracosapentaenoic acid, docosahexaenoic acid, and the like.
A normal feeding regimen can provide between about 300-1200 grams per day of lipid ingredient to a ruminant such as a lactating dairy cow.
The essential ionophorous antibiotic ingredient of an invention feedstock is added in a quantity which is effective for improving the health and productivity of ruminants. The content of the ionophorous antibiotic in the feedstock typically will be in the range between about 5-80 milligrams per kilogram DM of feedstock. For feeding lactating dairy cattle, a convenient measure is the provision of between about 0.1-2 grams of antibiotic ingredient per day per dairy cow.
Publications which describe ionophorous antibiotics include U.S. Pat. Nos. 3,839,557; 5,217,993; J. Anim. Sci. 58(No.6), 1461-1483, 1484-1498, 1518-1527 (1984); Appl. Environ. Microbiol., 55(1), 1(1989); J. Dairy Sci., 80, 921 (1997); and technical articles cited therein, incorporated by reference.
Ionophores are naturally occurring cyclic polyethers containing multiple furan and tetrahydropyran structures. Ionophores are anabolites produced by bacteria:
An ionophore is utilized in its natural form, or in the form of a physiologically acceptable derivative such as a sodium salt of the natural product or an analog thereof.
Ionophores differ in cation selectivity in their effect on microbial fermentation and biohydrogenation by ruminal bacteria. Monensin and nigericin are monovalent antiporters with selective binding affinity for Na+ and K+. Tetronasin is a divalent antiporter that preferentially binds with Ca2+ and Mg2+.
A main effect of ionophore presence in a rumen is a lower molar percentage of acetate, and a higher molar percentage of propionate. An ionophore also decreases methane production in the rumen.
An ionophore inhibits the rate of biohydrogenation of an unsaturated fatty acid such as linoleic acid under ruminal conditions. Any biohydrogenation of linoleic acid that occurs, yields less stearic and more oleic acid. There is an increased total of C-18:2 conjugated acids, mainly because of a cis-9, trans-11 C-18:2 isomer. This higher ruminal survival rate of unsaturated fatty acids is reflected in the profile of bypass lipid in the digestive tract. Consequently, the nutritional quality of the milk product from a lactating ruminant is enhanced for human consumption.
It appears that an ionophore reduces methane production by inhibiting the growth of gram-positive bacteria that produce hydrogen, and this moderates the biohydrogenation in the rumen. Effectively, a dietary ionophore alters lipid metabolism in the rumen, thereby increasing the unsaturated fatty acids in ruminal microbes and in the abomasum digesta.
The use of a lipid derivative having rumen-bypass properties in a present invention feedstock has additional advantage with respect to biohydrogenation by ruminal bacteria. Unsaturated fatty acids require a free carboxyl group in order to undergo biohydrogenation. A present invention lipid derivative with rumen-bypass capability permits increased passage of unsaturated fatty acids out of the rumen into the digestive tract.
In another embodiment this invention provides a lipid supplement for enriching the nutritive value of ruminant feedstock, wherein the supplement is a blend of ingredients comprising (1) unsaturated fatty acid derivative having rumen-bypass properties; and (2) between about 0.5-20 weight percent of cyclic polyether ionophorous antibiotic.
The unsaturated fatty acid derivative in the supplement can comprise fatty acid calcium salt and/or fatty acid magnesium salt and/or fatty acid amide. The unsaturated fatty acid moiety can comprise oleic acid and/or linolenic acid.
The ionophorous antibiotic ingredient in the lipid supplement can comprise monensin and/or nigericin and/or tetronasin and/or a physiologically acceptable derivative thereof.
In a further embodiment this invention provides a method of improving the lactational performance of ruminants, which consists of feeding a lactating ruminant with a feedstock comprising (1) a nutritionally balanced basal ration; (2) between about 2-20 weight percent, on a dry weight basis, of a lipid ingredient comprising unsaturated fatty acid derivative having rumen-bypass properties; and (3) between about 5-80 milligrams of cyclic polyether ionophorous antibiotic ingredient, on a dry weight basis, per kilogram of feedstock.
In a feeding regimen for lactating dairy cattle, it is preferred that the lipid ingredient in a feedstock comprises at least about 40 molar percent of unsaturated 18-carbon fatty acid constituents, so that the recovered milk product has increased nutritive and health values for human consumption.
Recent research also has shown that there are numerous components of milk fat that are potential anticarcinogenic agents [J. Nutr., 127, 1055 (1997)]. These include CLA, sphingomeyelin, butyric acid, and ether lipids. CLA is of the greatest interest. This CLA isomer of linoleic acid, formed mainly as a product of the ruminal biohydrogenation process, is the most potent natural anticarcinogen in foods [Cancer (Suppl.), 74, 1050 (1984)]. CLA occurs in milk fat in a quantity of about 0.3-0.8% of the total milk fat.
In addition to its anticarcinogenic effects, CLA has been reported to influence body composition (less fat, more muscle), improve bone growth, and stimulate immune function.
It is also known that increasing the consumption of omega-3 unsaturated fatty acids has human health benefits, particularly with alpha-linolenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Omega-3 unsaturated fatty acids have been shown to reduce hypertension, and to lower serum lipids [Atherosclerosis, 62, 259 (1986)]. Omega-3 unsaturated fatty acids also are recognized as important dietary compounds for preventing coronary heart disease and alleviating inflammatory conditions, and for retarding the growth of tumor cells.
The following Example is further illustrative of the present invention. The components and specific ingredients are presented as being typical, and various modifications can be derived in view of the foregoing disclosure within the scope of the invention.